The present invention is in the technical field of wheelchairs. More particularly, the present invention is in the technical field of wheelchairs able to travel over a plurality of surfaces, both “on-road” and “off-road.”
For the purposes of this application, wheelchairs can be broken down into two categories: motor-propelled and manually propelled. Motor-propelled wheelchairs feature a motor, electric or other, which provides the energy necessary to move the wheelchair around. Manually propelled wheelchairs rely on the user or another to provide the energy necessary to move the wheelchair. The present invention and the wheelchairs discussed in this application are human propelled.
Traditional wheelchairs date back to the 6th century C.E. China and have been refined over thousands of years. In general, traditional wheelchairs feature a seat, backrest, two armrests, two footrests, two large rear wheels and two small front caster wheels. In addition, traditional wheelchairs typically feature handles on the top left and top right corners of the seat so that another may push the wheelchair and user.
Traditional wheelchairs feature thin rear wheels of a large diameter, often 50 cm-60 cm in diameter. Two thin caster wheels of a much smaller diameter on the front of traditional wheelchairs allow the user or the person pushing the wheelchair to easily turn it as necessary. Taken together, the wheels and design of a traditional wheelchair provide the most-efficient means of travel possible, as long as the user is on solid ground and a relatively smooth surface.
Once a traditional wheelchair is taken off a paved surface, its deficiencies become readily apparent. The caster wheels on the front do not track in a straight line when the user moves a traditional wheelchair forward on sand or other soft surfaces. The thin nature of the front and rear wheels of a traditional wheelchair which make it so well-suited for paved surfaces make it poorly suited for unpaved surfaces.
Prior art discloses all terrain and beach wheelchairs encompassing a plurality of designs. The majority of wheelchairs in the prior art utilize designs similar to those of traditional wheelchairs, incorporating fatter, knobby tires similar to those on a mountain bike, or incorporate much wider front and rear wheels to provide floatation on softer surfaces, such as sand. All terrain wheelchairs currently on the market suffer from one or more of the following problems: difficult to push/pull; non-ergonomic pushing handles; difficulty of entry due to high tubing and low seat height; PVC frames which flex excessively and are not well constructed; and the likelihood of ejecting the passenger forward during abrupt stops.
The goal of the present invention is to remedy the deficiencies found in traditional wheelchairs and to offer an all terrain wheelchair superior to those on the market. The inventor believes the present invention offers a combination of novel features that, taken in combination, demonstrate a drastic improvement over the prior art.
The inventor has performed a search of the prior art and believes the present invention is a new and useful invention for which patent protection is warranted.